Users of apparatus, such as conveyor systems, often wish to monitor physical characteristics of the apparatus during its operation for various reasons. For example, a user may wish to monitor a speed at which a conveyor belt of the conveyor system is moving to ensure that it is moving within a desired speed range. As another example, the user may wish to monitor a temperature of a part of the apparatus to ensure that the temperature of the part does not exceed a predetermined threshold. Particularly, users sometimes wish to monitor a temperature of a part of the apparatus that is known to overheat or heat up in advance of failure. For instance, it has been determined that a rubber bead trimming some conventional conveyor belts heats up when subjected to unbalanced forces. Such unbalanced forces may result from improper alignment of elements of the apparatus driving or guiding the belt by way of the bead. By determining that the trimming bead is heating undesirably, the user may halt the conveyor for inspection and possible maintenance in advance of failure and other damage or injury.
Sensors for monitoring many physical characteristics are relatively inexpensive. However, positioning one or more of the sensors at locations remote from a central processor, such as about a warehouse, can be prohibitive due to a relatively high cost of wiring power to the sensors and also a relatively high cost of providing communication wiring for transmitting the sensor output signals to the central processor.